A ramp-lock quick-connect fitting is adapted to be placed between conventional type fittings on pipes and tubes, such as quartz pipes and synthetic resin tubes used in chemical processing systems for semiconductor device fabrication. The quick-connect fitting includes a first coupling member having a pipe receiving section adapted to receive a conventional fitting on a pipe, and a ramp support section with a pair of spiral ramps formed therearound. The quick-connect fitting also includes a second coupling member that sealingly engages the first coupling member. An extension portion of the second coupling member is adapted to receive a conventional fitting on a tube. A locking collar is movably engaged with the second coupling member and has a pair of lock members disposed on an interior surface of the collar that slidably engage with the spiral ramps when the collar is rotated around the ramp support section of the first coupling member.